Vibrator device



v Sept. 15, 1936. L. J. WAHL VIBRATOR DEVICE Filed Jan. 4, 1934 Patented Sept. 15, 1936 UNITED STATES VIBRATOR DEVICE Leo J. Wahl, Sterling, 111., assignor to Wahl Clipper Corporation, Sterling, 111., a corporation of Illinois Application January 4, 1934, Serial No. 705,213

2 Claims.

My invention relates to electromagnetic devices in which an electromagnet driven from an alternating current source operates to attract an armature which in turn drives a work piece such as a massage implement.

The invention has for its principal object the combination with such devices of means to modify the alternating current fed to such device in such fashion as to cause the electromagnet to attract its armature for a certain time and then release it for a similar time whereby to allow the armature ample time to retract without hindrance on the part of the electromagnet.

In devices of this character, particularly where they are used to operate a massage element, the attractions by the electromagnet on the ordinary sixty cycle current supply are of such rapidity as to seriously limit the penetrating qualities of the massaging action. Normally the armature is attracted in each half wave of a cycle thus giving 120 attractions per second. I

I find that, if I can eliminate the alternate attractions and thus give more time for the armature to retract or move away from the magnet by kinetic spring energy, the effect of the massage element is much more pleasing and beneficial than the high speed type of vibration. This is particularly true in the case of the spring mounted armature since the attraction of the electromagnet is cut off for a substantial period of time to allow the spring to move the armature and its implement outwardly to deliver its blow with perfect freedom and at such a rate as to pro-- duce a much better penetration than I have been able to obtain with the vibrator actuated on each impulse of alternating current to produce 120 vibrations per second.

I find also that actuation of the vibrator with this improved action may be accomplished with improved results, if, instead of utilizing a rectifier capable of rectifying current at the full volt-I age applied, I use arectifier which is normally capable of rectifying the current at only a fraction of such voltage. For example, I may use a rectifier normally expected to rectify currents at voltages of approximately one-fourth the voltage applied. I propose to obtain the above action by utilizing a rectifier in circuit with the coil of the electromagnet, and preferably I use a rectifier of the dry contact plate type such as the well known copper oxide rectifier. With such a rectifier, I find that I get very good results by using a rectifier having a much smaller number of plates than is required to rectify the 110 volt current supplied.

I will describe the preferred form of my invention by reference to the accompanying drawing wherein- Fig. 1 is an elevation partly in section of the device showing the vibrator and the rectifier element;

Fig. 2 is a section on the line 2-2 of Fig. 1; and 10 Fig. 3 is a diagrammatic view illustrating the electric circuit utilized.

Referring now in detail to the drawing, I show at 5 an electromagnetic vibrator such as that shown in my prior U. s. Patent 1,832,437. This 15 vibrator has the spring mounted non-polarized armature 6 carrying the massage implement or work piece I. A suitable coil 8 and core 9, not shown in Fig. 1 but illustrated diagrammatically in Fig. 3, form the electromagnet which attracts the armature 6 upon the passage of current through .the coil 8 against the tension of the spring which carries the armature thus to create a vibrating movement of the work piece I in response to the current flow through the winding of the electromagnet.

In order to accomplish the purposes of my invention, I combine with this vibrator a suitable rectifying device III which may be of the well known dry contact type of rectifier such as the copper oxide type wherein a series of plates such as l l are adapted to permit current to pass in one direction through them while they oppose current passing in the opposite direction. The details of operation of such rectifiers are, of course, well known and will not be further described here except in so far as it is necessary to explain the features of the invention. It will be noted from the diagrammatic view in Fig. 3 that one of the leads l2 from an alternating current 40 source passes through the rectifier l0 and passes then from the rectifier over lead I3 to the winding 8 of the electromagnet. The other lead [4 goes directly to the opposite terminal of the winding. The rectifier l0 and electromagnet are thus in 45 series circuit. The rectifier is preferably housed in a suitable casing such as I5 in which it is mounted by means of the screw bolt l6 and nut II, the insulating sleeve l8 serving with the insulating disks l9 and 20 properly to align the rectifier from the casing. The leads l3 and I! lead to an ordinary socket l6 mounted in the casing l5, and the plug I1 is plugged into the socket Hi to connect the vibrator 5 in circuit with the rectifier. Leads l2 and H, of course,

form a cord which may have the usual plug for insertion in. a wall socket to receive current from an alternating source.

It will be evident, it is believed, from the above description that the rectifier will permit current to fiow freely in one direction through the coil I so that during one half cycle of the alternating current the winding of the electromagnet will be energized thus to attract the armature 8. When the alternating current reverses, however, its fiow is opposed by the rectifier for the next half cycle thus deenergizing the winding for a substantial period to allow the spring mounting of the armature to swing the armature outward and to cause the masage implement I to deliver its working blow unhampered by any action of the electromagnet.v It is well known, of course, that these rectifiers such as the copper oxide rectifier described do not completely prevent current flow in the reverse direction, but this does not detract from the effectiveness of its operation for my purpose. In fact, a slight reverse fiow of current merely tends to overcome the residual magnetism of the core of the electromagnet, and this in a way increases the efilciency of the device.

An unusual and quite unexpected result is obtained by reducing the number of plates in the rectifier in this combination. The vibrator and rectifier operate just as well with less than half the number of plates normally required to rectify the 110 volt supply. In fact the rectifier mentioned is satisfactory when I use about 25% of the number of plates required in a complete rectifier for volts. When I use only 25% of the number of plates normally used to rectify current in a 110 volt circuit it is evident that only a small percentage of the current flowing in the reverse direction is cut off. The vibrator seems to have even more power than with a complete rectifier.

Although I do not fullyunderstand the causes of this greater power, I believe that one explanation for this unexpected action of the vibrator with the small rectifier may be that the armature is attracted with a greater force by the current flowing unrestrictedly in the one direc tion through the small rectifier because there is less resistance in the small rectifier. Then as the current rises during the start of the reverse fiow, it is initially blocked by the small rectifier or the combined action of the rectifier and the residuai magnetism of the core thus tending to more quickly collapse the magnetic field and initially allowing the armature to recede from the attracted position with practically no magnetic pull to oppose it, and, when the voltage limit of the rectifier is reached and current does fiow in the reverse direction, the armature is so far away from the pole face of the electromagnet that the force exerted has a nesligible efi'ect upon the armature movement which is then due to the kinetic energy of the spring mounting of the armature.

It is still necessary to time the spring mounted armature. but the tuning may be to cycles as in the case of the unrectified power or to 00 cycles, and the vibrator works very well with the rectifier in circuit in either case.

While I have shown the rectifying unit as being mounted in a separate casing ll adapted to rest upon a fioor or upon a shelf, it is obvious, ,of course, that this element may be built so as to plug directly into awall socket if desired or in the vibrator itself in either case in series circuit with the vibrator.

From the above description, it is believed that the construction and operation of this device will be clear to those skilled in this art and the advantages thereof readily apparent.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent is:

l. A vibrator of the character described comprising an electromagnet having a winding, and means to connect said winding to a source of alternating current, an armature, a work tool thereon and a rectifier of the dry contact plate type in circuit with said winding, said rectifier having a number of plates less than half the number which normally is required to rectify the voltage of said alternating current source.

2. A vibrator of the character described comprising an electromagnet having a winding, and means to connect said winding to a source of alternating current, an armature, a work too] thereon and a rectifier of the dry contact plate type in circuit with said winding, said rectifier having about one-fourth the plates required to rectify the voltage of said alternating current source.

LEO J. WAHL. 

